MIAMI—Freedom to Marry national campaign director Marc Solomon provided an illuminating overview of his successful 13-year battle for marriage equality, at the 2015 Global PR Summit today in Miami.

Solomon, in conversation with Cohn & Wolfe Americas CEO Jim Joseph, pointed out that the success was far from assured, particularly after a string of losses in key ballots.

However, a focus on communication, data and influencer marketing ultimately paved the way for the pivotal Supreme Court decision that declared gay marriage legal.

"Ultimately this campaign was about selling gay people to America, selling same sex marriages," said Solomon. "We had to gain market share. We had to grow our supporters nationwide. We had to figure out how we could grow states and win states."

To do that, the campaign focused on connecting with people who could be won over, after research revealed "challenging" attitudes towards gay people.

"What we knew we had to is connect to people and explain to them who we were and why we wanted to marry," explained Solomon. "Explaining that we wanted to marry out of the same reasons as you do. We were asking people to reconsider something that had been ingrained since day one."

This involved some emotional advertising, which featured real people explaining how their attitudes towards gay marriage had changed.

The use of big data also proved important, with the campaign enlisting micro-targeting firms from both the right and left to help it identify potential supporters. In Maine, for example, that included personal conversations with targeted voters — a strong field camapign that ultimately led to success in the state.

Joseph pointed in particular to the campaign's use of classic influencer marketing techniques to sway opinion. For Solomon, this involved finding spokespeople that would surprise Middle America, such as figures from the military, Republicans and the clergy.